372 The Diseases of Animals 



TEXAS, OR SOUTHERN CATTLE FEVER 



This disease is also called Spanish, splenic, acclima- 

 tion, and (in Australia) "tick" fever. In some regions, 

 owing to the color of the urine, the disease is called 

 "redwater." It is caused by a microscopic animal 

 germ (Piroplasma bigeminum) , and is transmitted from 

 southern to susceptible northern cattle by means of 

 the southern cattle-tick (Margaropus annulatus) . Fig. 

 52. Southern cattle coming from the region south of 

 central Virginia and Tennessee, and east of central 

 Indian Territory and Texas, and from Lower Cali- 

 fornia, come from a permanently infected territory, 

 and have the germs of Texas fever in their blood; but 

 they do not suffer from Texas fever, as they possess 

 immunity. The region described is south and east of 

 the quarantine line established by the United States 

 Department of Agriculture, and marks the northern and 

 western limits of the region permanently infested by 

 the southern cattle -tick. 



When southern cattle are brought north during the 

 warm season of the year, the mature female ticks drop 

 from their bodies and lay a great number of eggs that 

 hatch in from two to six weeks. The young ticks 

 are quite active and show a tendency to crawl up on 

 grass rather than side wise. When susceptible north- 

 ern cattle pass over the tick - infested ground, these 

 young ticks get on their legs, crawl up to their bodies 

 and soon bury their mouth -parts in the thin skin on 

 the belly or the inside of the thighs. In this manner 

 they transmit the germs of the disease. About ten 



